The present inventor and others discovered that a hypersonic sound, which was a non-stationary sound abundantly containing super-high-frequency components exceeding the audible frequency upper limit, introduced a fundamental brain activation effect of increasing the regional cerebral blood flow of the fundamental brain, including the brain stem, thalamus and hypothalamus, and the fundamental brain network (fundamental brain network system) of a human being listening to the sound and boosting α rhythm of the brain wave power of an index of the fundamental brain activation, and had the effects of heightening the aesthetic sensibility inclusive of receiving of sounds pleasantly, beautifully and movingly, reducing stress, rationalizing the activities of the autonomic nerve system, the endocrine system and the immune system, and comprehensively improving the mental and physical states, i.e., a hypersonic effect, by contrast to which the fundamental brain activity was more deteriorated than in a background noise state when he or she was listening to a sound containing no super-high-frequency component (See, for example, the Patent Documents 1 to 4 and the Non-Patent Documents 1 and 2).
In addition, the present inventor and others have revealed that, by contrast to the fact that the natural environmental sounds of the tropical rain forests, which are the most powerful candidate of the environments where the human genes had been formed through evolution, abundantly contained super-high-frequency components that largely exceeded 20 kHz at the human audible frequency upper limit and had a complicatedly changing structure capable of introducing the fundamental brain activation effect, environmental sounds in cities where the modern people lived contained almost no such super-high-frequency components and deteriorated the fundamental brain activity (See, for example, the Patent Document 5 and the Non-Patent Documents 3 and 4).
The fundamental brain activated by the hypersonic sound serves as an important base of the neural circuit inclusive of the monoamine nerve system and the opioid nerve system closely related to the control of human emotions and behaviors. Therefore, it has been discovered that the activity disorder of the fundamental brain and the neural network projected on the entire brain from there leads to various mental and behavioral disorders. Further, the fundamental brain, which is the ultimate center of the autonomic nerve system and the endocrine system, controls the immune system via them and bears a function to maintain the homeostasis of the whole body through these and a biophylactic function. Therefore, the disorder of the fundamental brain activity has a close relation to the induction of the lifestyle-related diseases that are rapidly increasing in the modern society by incurring breakdown of the homeostatic function and the biophylactic function.
Therefore, paying attention to the fact that the aforementioned mental and behavioral disorders and the lifestyle-related diseases and the like are increasing specifically and rapidly in the modern society, it is highly possible that a cause is ascribed to the fact that the sound environments surrounding the modern people largely deviate from the specific sound structure characterizing the environmental sounds of the tropical rain forests, which are the most powerful candidate of the environments where the human genes have been evolutionally formed, and particularly the complicatedly changing super-high-frequency components drop out, consequently causing the disorder of the fundamental brain activity.
On the other hand, reproducing the tropical rain forest natural environment as it is in the modern cities does not become a realistic solution method counterbalancing the urgency of the aforementioned problems that the modern societies confront in terms of climate and biological conditions and also in the aspect of the needed time and the amount of a social investment cost. Accordingly, a method for solving the aforementioned problems in the aspects of psychosomatic health that the modern people confront is proposed by using a vibration signal having a specific structure to introduce the fundamental brain activation effect and a vibration generating apparatus capable of generating it, generating a vibration to introduce the fundamental brain activation effect in a manner similar to that of the tropical rain forest environmental sounds suited to the design of the human genes and applying the same to the modern people, thereby introducing the fundamental brain activation effect (See, for example, the Patent Document 5).
However, almost all of the audio signals in the digital formats outputted from compact discs (CD), mini discs (MD) and those recorded in solid memories of portable players, which are audio information media widely popularized in the modern society, and the audio signals in the digital formats distributed and delivered via broadcastings and telecommunications can neither record nor reproduce super-high-frequency components, and therefore, they are unable to generate a hypersonic sound and to activate the fundamental brain.
On the other hand, it is recently becoming possible to use digital media, which have formats capable of recording, transmitting and reproducing to a range that largely exceeds the audible range upper limit, such as super audio CD (SACD), DVD audio, soundtracks of blu-ray disc (BD) and network distribution by high-speed optical communications or the like. However, the vibration signals recorded in the recording media, i.e., the contents contain no super-high-frequency component in these due to limitations in the vibration generating function owned by the sound sources and limitations in the capability of the recording and editing apparatuses and the like, and therefore, it is customary that the hypersonic sound cannot be generated and the fundamental brain activation effect cannot be introduced.
Further, the present inventor and others revealed that, when an artificial signal of a white noise or the like was applied as super-high-frequency components to a listener with the audible range components, or the vibration components in the audible frequency range, the hypersonic effect was not induced even if sufficient super-high-frequency components are contained (See, for example, the Non-Patent Document 2). Moreover, none of a sine-wave-like signal having a peak at a specific frequency, its harmonic sound and super-high-frequency components of a quantization noise entailed by a high-speed sampling 1-bit quantization system or the like similarly produce the hypersonic effect. Further, it is recently revealed that super-high-frequency components, which are composed of a sine-wave-like signal having a peak at a specific frequency and are generated from artificial objects of electronic equipment and the like, introduce negative effects of unpleasant sensation, escape behavior and so on in human beings and animals to which they are applied, and they are used as an apparatus for rejecting young people and an apparatus for repulsing mice (See, for example, the Non-Patent Documents 5 and 6).
These findings suggest that, in order to introduce the fundamental brain activation effect by the hypersonic effect, it is not proper to merely apply super-high-frequency components exceeding the audible range upper limit, but it is necessary that those super-high-frequency components have a certain specific structural feature, whereas the vibration of the super-high-frequency components having a certain peculiar structure different from it has a risk of possibly exerting a negative influence on the physiological states of human beings and animals. However, such a structural feature that the super-high-frequency components of the vibration that can introduce the fundamental brain activation effect should have has not been clarified thus far. Therefore, even if the digital formats capable of recording, transmitting and reproducing super-high-frequency components in a manner similar to that of the super audio CD (SACD), soundtracks of blu-ray disc (BD) and network distribution utilizing high-speed optical communications and the like are made usable, it is unclear what sort of structural feature should be owned by the vibration signals recorded and transmitted there in order to introduce the fundamental brain activation effect.